As an apparatus having a coating capacity several times the capacity of an ordinary coating machine, there is known a disktype electrostatic powder coating apparatus which distributes radially and outwardly from a disk particles for coating articles to be coated which move around the disk.
From the stand point of how to distribute the powder particles, such disk-type powder coating apparatus are generally classified into non-rotating disk-type apparatus in which a disk is not rotated as disclosed in U.S. Pat. No. 3,843,054 and Japanese Patent Publication No. 56-35900, and rotating disk-type apparatus in which a disk is rotated as disclosed in U.S. Pat. No. 3,735,924 and No. 3,942,721. In the non-rotating disk-type apparatus, the powder particles are distributed by means of jet streams of assist air. In the rotating disk-type apparatus, the powder is distributed by centrifugal force caused by rotation of the disk.
More specifically, in the non-rotating disk-type apparatus disclosed in Japanese Patent Publication No. 56-35900, for example, a tube extending vertically toward a central portion of a disk has air ejecting apertures for orienting the powder particles, such that the particles supplied from the tube to the disk are distributed radially outwardly from the disk by means of the assist air ejected through the apertures.
In the rotating disk-type apparatus disclosed in U.S. Pat. No. 3,735,924, a powder supplying tube is arranged to open above a central portion of a rotating disk, and the powder particles supplied from the tube to the central portion of the disk are distributed radially a outwardly from the disk by a centrifugal force caused by rotation of the disk. The disk-type electrostatic powder coating apparatus, either of the rotating type or of the non-rotating type, is constituted such that a single coating apparatus applies the powder particles onto a plurality of articles around the disk. Therefore, it is important to uniformly distribute the powder particles radially outwardly from the disk in the circumferential direction of the disk.